1. Field of the Invention
The present invention relates generally to an assembly for use in an electro-photographic image forming device and, more particularly, to a bearing plate for rotatably supporting a photoconductor drum in the assembly.
2. Description of the Related Art
In a typical in-line color electro-photographic imaging process, latent images are formed on one or more photoconductor drums, which are in turn each developed using a predetermined color of toner. A color image forming device may include a plurality of photoconductor drums, each corresponding with a desired color, for example, black, magenta, cyan and yellow. Each toner color forms an individual image of a single color that is combined in layered fashion to create the final multi-colored image. A mono electro-photographic image forming device typically includes at least one photoconductor drum. The developed images are transferred from the photoconductor drum(s) to a toner receiving surface such as an intermediate transfer medium or a media sheet (such as paper) that travels past the photoconductor drum(s).
The photoconductor drum(s) include a drum body and support members, such as bearing plates. The drum body has a hollow tubular shape. The support members rotably support the outer peripheral surface of the photoconductor drum body. Typically, the photoconductor drum rides inside a thin plastic wear strip or cap bearings that are mounted in a mirror-image fashion on each end of the photoconductor drum. The bearing plates sit in a V-notch block positioned adjacent each end of the photoconductor drum.
In this configuration, an out-of-round photoconductor drum can cause AC process print registration problems. These registration problems may be caused by positional error of a cartridge station relative to another cartridge station in the photoconductor drum's process direction. Registration problems may also be caused by sinusoidal motion of an out-of-round photoconductor drum resulting from the drum not being restrained as it rides upon the leading and trailing sides of the V-notch block.
In this configuration, the bearing plates possess bi-lateral or mirror-image symmetry with respect to one another and are installed on each end of the photoconductor drum, magnifying the effect of any dimensional error in the bearing. Further, the photoconductor drum, the charge roller, and the cleaner blade are mounted to a cleaner housing, a large plastic part with poor dimensional accuracy. Dimensional variations between electro-photographic components, for example, between each bearing plate, may cause skew between the media sheet and the photoconductor drum(s) as well as cartridge-to-cartridge variation such that, for example, a first color toner image will be shifted from a second color toner image. Accordingly, it will be appreciated that an assembly is needed that decreases the variation between electro-photographic components to decrease the occurrence of skew and increase dimensional control.